Cable, such as fiber optic communication cable, is often provided underground in great lengths, and may even extend for many miles. It is known in the art to bury the cable in the ground so that the area above-ground is not cluttered with the cable and its respective support apparatus. Furthermore, by positioning the cable underground, it is more protected from the weather and other potentially damaging circumstances.
It is also known in the cable art to position the cable within a conduit in order to more fully protect the cable during in-ground installations. The conduit, which is often formed from lengths of polyvinyl chloride tubing or the like, is laid in the ground, after which a rope is placed in the conduit either by blowing or rodding. The rope, in turn, is attached to one of the communication cables. By pulling the rope from one end of the conduit, the cable is drawn through the conduit into position. Once placed within the conduit, the cable is protected from damage which may be caused by weather, water, and the like.
When a conduit is in place, it may be subsequently desired to run a second communications cable at the same location. As such, it would be desirable from a cost and time standpoint to make use of the dead space within an existing conduit, rather than lay a new length of conduit. However, it has been found that it is difficult to merely insert a second cable into a conduit that already contains a first cable. When a rope is blown or “snaked” into a conduit already containing a cable (or when a second cable is “snaked” through a conduit with a pre-laid cable), the rope (or cable) is often impeded by the first cable. In such cases, the rope (or second cable) becomes tangled with, or twisted around, the first cable, causing damage to the cables.
It has been suggested to provide a divider to be inserted into a conduit in order to separate the conduit into discrete sections, thus making insertion of the second cable easier. A problem has been encountered in that when conduit is placed over long distances, undulations will invariably occur therein. Also, planned curves, such as at underpasses or the like, will often be encountered rendering the placement of known dividers therein difficult, if not impossible.
A need exists, therefore, for a device to separate or partition a conduit, such as an underground communication cable conduit, into discrete sections. The device must be capable of being inserted into a conduit that is already in place, which may undulate over many miles, and which may have sharp turns therein. A need also exists for a partitioning device which will provide for improved use of the space within a conduit.
U.S. Pat. No. 6,304,698 provides one solution to the problems described above. While particularly effective at partitioning relatively large conduits (that is, those having an interior diameter of at least four inches), it was discovered that improvements to the innerduct configuration and to the fabric construction would reduce the pulling tensions experienced by the innerduct and cables during installation. As a result, the likelihood of cable damage during installation is minimized. Additionally, the fill ratio, particularly for small diameter conduits, is increased, when using the present innerducts. Such improvements to the textile innerduct of the '698 patent are the subject of this disclosure.